Get ya a good kit, with good clutches either red or green, make sure you get NEW steels and not the ones they send though a tumbler. Maybe ad a TF-2 Shift kit. Bands, seals and bushings. Bulkpart.com has a lot of this stuff. Check your kits be sure they at least come with all the basics.
A bolt in HD sprag is good insurance too. Flush out your converter & the cooler & lines real good before you put it all back together. A local trans shop can help with the converter flushing & just use mineral spirits & compressed air for the cooler & lines.
Get a deluxe kit. transtar 12008c If you want to go with other clutches/steels, you can.
Ask Tony, 70AARCuda what he's bought recently for rebuilding 904's. He only beats his with a transbrake... I'm sure he'll give you a list of parts he uses.